Content
The appearance of yellow leaves on tomatoes indicates a violation of the rules for growing plants. There are several explanations why Tomato leaves turn yellow. This includes disruption of the microclimate when growing tomatoes, lack of fertilizers, and the spread of diseases and pests.
Causes of yellowing leaves
Microclimate disturbance
For normal growth, tomatoes require the maintenance of certain climatic conditions. Typically, leaf drying is associated with incorrect temperature conditions and non-compliance with watering rules. If the tomatoes turn yellow and leaves are dryingWhat to do depends on the cause of the microclimate disturbance.
Temperature
For normal growth, tomatoes require a temperature of 20 to 25 degrees during the day. At the same time, at night its value should remain at 18-20 degrees. Sharp temperature fluctuations negatively affect the condition of plants.
When temperatures rise above normal, plants wilt. The first sign of this process is yellowing of the leaves of the tomatoes. If measures are not taken in a timely manner, the tomatoes’ inflorescences will begin to fall off.
Glass in a greenhouse can be covered with lime to reduce exposure to sunlight. To reduce the temperature, containers of water are placed between the bushes.
If tomatoes grow in open ground, then a canopy can be built over them. Its functions will be performed by white fabric.
Watering tomatoes
Violation of the moisture regime also leads to drying of plant leaves. Tomatoes require abundant but infrequent watering. Due to the developed root system, tomatoes can receive moisture and nutrients from a depth of up to one meter.
With sufficient rainfall in open ground, plants will require less watering. Moisture should be applied at the root. It is not allowed to get on the stems and tops of tomatoes. Otherwise it will cause leaf burn.
Watering tomatoes requires warm water. It is best to use rainwater that has been warmed by the sun. Plants should be watered in the morning or evening in the absence of direct sunlight. The intensity of watering increases during the flowering period of tomatoes.
Mulching will help maintain the required level of soil moisture. To do this, straw and compost are placed on the soil surface. Mulch avoids loosening and reduces the amount weed.
If tomato leaves turn yellow, this is the first sign of lack of moisture. Therefore, it is imperative to review the irrigation scheme and make adjustments if necessary.
Fertilizer shortage
The appearance of yellowness on plant leaves is often associated with a lack of nutrients in the soil. This is usually observed on tomatoes in open ground or large greenhouses, where it is difficult to control the quality of the soil.
Nitrogen
With a lack of nitrogen, tomato leaves turn yellow, after which the dried tops fall off. If timely measures are not taken, the bush will begin to stretch out, and the young shoots will become pale and small.
Due to nitrogen, plant growth improves and green mass increases. Tomatoes can be fed with urea. A bucket of water requires 40 g of this substance. The resulting solution is used for spraying plantings.
When using nitrogenous fertilizers, the dosage of the substances must be observed. Frequent fertilizing with nitrogen will lead to increased growth of tomato tops. If after fertilizing the condition of the plants has improved, then further application of nitrogen should be stopped.
Potassium
With potassium deficiency in tomatoes, old leaves turn yellow and dry, and young tops curled into a boat. Small spots appear along the edges of the leaf plate, after which they merge into a single line. As a result, the tomato leaves dry out.
You can fertilize plants with potassium at any stage of the growing season. This microelement is especially important for adult tomatoes when the fruits ripen.
One of the feeding options is the use of potassium sulfate. After its use, the content of vitamins and sugars in fertilized vegetables increases, and the plants become resistant to diseases.
To feed tomatoes, 40 g of potassium sulfate per bucket of water is required. Plants are watered at the root or sprayed on the leaf.
Magnesium
With a lack of magnesium, yellowness first appears between the veins, then the leaf blade curls.
Magnesium sulfate will help compensate for the deficiency of this element. 40 g of the substance are diluted in 10 liters of water, after which they are applied to the roots of plants. For spraying tomatoes, the specified rate is halved.
Magnesium allows plants to better absorb nitrogen, calcium and phosphorus. As a result, the development of tomatoes is activated, productivity increases and the taste characteristics of the fruit improve.
Sulfur
Sulfur deficiency is determined by the light green tint of the leaves, which gradually turn yellow. In this case, the veins become red. With a prolonged lack of sulfur, the stem weakens and becomes brittle.
Ammoniated superphosphate will help compensate for the deficiency of this element. This substance is highly soluble and provides tomatoes with sulfur and potassium.
Iron
Lack of iron causes chlorosis. This disease is characterized by the appearance of yellow leaves, with the veins remaining green. Over time, the tops of the tomatoes lose color and the plant stops developing.
Iron sulfate, on the basis of which a solution for spraying is prepared, will help fill the deficiency. 5 g of the substance is added to a bucket of water, after which the treatment is carried out. A week later the procedure is repeated.
Development of diseases
The cause of yellowing of tomato tops is often diseases. Most of them develop when excess humidity, dense plantings and other disturbances in plant care appear. Special drugs are used to combat diseases.
Fusarium
The spreader of fusarium is fungal spores. The lesion covers the roots, stems, tops and fruits of tomatoes. Signs of the disease can occur at any stage of plant development, however, most often they can be detected during fruit formation.
With fusarium blight, the tomato leaves turn yellow, which then curl up and fade away. A section of the stem reveals brown vessels. The disease occurs from below, after which it moves to the apex.
When fusarium appears, it is recommended to remove and burn the plant to avoid the spread of infection. To prevent the disease, you need to treat the seeds and soil with fungicides before planting, plant the plants at a distance of 30 cm from each other, remove weeds, and loosen the soil.
Late blight
If the leaves on tomatoes turn yellow, this may be a sign of late blight. This is a fungal disease characterized by the presence of brown spots on yellowing leaves.
When late blight appears, all yellowed leaves must be removed. The humidity level in the greenhouse should be reduced by ventilating it.
Healthy bushes are treated with biological preparations (Fitosporin, Trichophyte, etc.). After using them, the fruits must be thoroughly washed and only then used for food.
If there is more than a month left before the start of the harvest, then it is allowed to use chemicals (Ridomil, Quadris, Hom). They are also used after harvest to disinfect the greenhouse and soil.
Additionally, tomatoes are treated with a solution based on iodine and milk (15 drops of iodine per 1 liter of milk and 9 liters of water). The procedure is carried out by spraying the plants.As a result, a film is formed on the surface of the tops, which prevents the penetration of harmful bacteria.
Pest Spread
The main pests of tomatoes are whiteflies, aphids, and spider mites. If these insects are detected, the plantings must be sprayed. Pests feed on the sap of plants and draw vitality from them. As a result, the upper leaves turn yellow and the plants gradually wither.
If there is more than a month left before the harvest, then the preparations “Inta-vir” or “Iskra” are used. These drugs have a paralytic effect on the nervous system of insects. The preparations do not harm tomatoes or the environment.
When the harvest time is less than a month, the drug “Biotlin” is used. This remedy has a quick effect.
Other reasons
Seedlings may turn yellow with insufficient lighting. Installing a white fluorescent lamp will help solve the problem. For tomatoes, the daylight hours should be 8-10 hours.
If the lower leaves of a tomato turn yellow, this indicates damage to the root system. This usually happens during deep loosening or during transplantation of plants to a permanent place. In this case, the color of the leaves will be restored when the tomatoes develop adventitious roots.
Conclusion
Why tomato leaves dry out depends on the state of the environment and the application of fertilizers. If the temperature rises above normal, you can completely lose the crop. Be sure to adjust the watering scheme for tomatoes and, if necessary, fertilize the plants.
If signs of disease or the presence of pests are detected, the tomatoes are treated.For this purpose, special preparations are used, on the basis of which a solution for spraying is prepared. Plantings can be processed using traditional methods that are as safe as possible for plants.
